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Background: Amblyopia is an ocular condition leading to structural and functional changes. The relationship between these changes is complex and remains poorly understood. (2) Methods: Participants included 31 children aged 5 to 9 years with strabismic (n = 9), anisometropic (n = 16) and mixed (n = 6) unilateral amblyopia, and 14 age-matched non-amblyopic children. The 95% and 63% Bivariate Contour Ellipse Area (BCEA), axial length, Foveal Avascular Zone (FAZ) area, center macular thickness and volume were assessed. The relationship between these parameters was explored. (3) Results: Statistically significant differences were found among the four groups in best corrected distance visual acuity (BCVA) (p < 0.001), BCEA 95% (p = 0.002) and BCEA 63% (p = 0.002), but not in the FAZ area, central macular thickness, central macular volume and axial length. Eyes with amblyopia had poorer BCVA and larger fixation instability than controls. Inter-ocular differences were more significant in patients with strabismic amblyopia, particularly in BCVA (p = 0.003), central macular thickness (p < 0.001) and central macular volume (p = 0.002). In amblyopic eyes, BCEA 95% and 63% were correlated with BCVA, but not with the FAZ area. (4) Conclusion: Amblyopia is associated with a reduction in fixation stability and BCVA, although there is a general lack of correlation with structural changes, suggesting a complex interaction between anatomy and function in amblyopia., Peer Reviewed, Postprint (published version)

Es un preprint del artículo publicado. El artículo se encuentra en libre acceso en la web del editor., PURPOSE. The Aniseikonia Inspector 1.1 (AI) is a new software product to measure aniseikonia using red-green anaglyphs. The purpose of this study was to test whether the AI is a valid and reliable test. METHODS. There were two groups of sample subjects: one at risk of aniseikonia, with anisometropia greater than or equal to 1.00 D (n = 29), and a control group (n = 45). The validity was studied by comparing the measured aniseikonia with the aniseikonia simulated with size lenses. The reliability was estimated by the Bland-Altman statistical method. RESULTS. The results showed that the AI underestimated aniseikonia and that the underestimation was greater in the horizontal than in the vertical direction. The reliability was low, with biases that were clinically insignificant, but the 95% limits of agreement were around +/- 2%. The behavior of the test was similar in both groups of subjects. CONCLUSIONS. The reliability of the AI is only moderate, and professionals are therefore warned to use the results of this test with caution., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, FALSE, pub

This retrospective study was conducted to evaluate the efficacy of the combined treatment of occlusion and active vision therapy in a total of 27 amblyopic children, including 14 strabismic and 13 anisometropic cases. For such purpose, changes in distance and near visual acuity as well as in the binocular function was evaluated during a two-year follow-up. In both amblyopia groups, significant improvements were found in distance and near visual acuity in the non-dominant eye (p < 0.001). In the strabismic amblyopia group, the percentage of patients with binocular function score (BF) > 3.3 decreased significantly from a baseline value of 64.3% to a two-year follow-up value of 7.1% (p < 0.001). In the anisometropic amblyopia group, this percentage also decreased significantly from a baseline value of 15.4% to a two-year follow-up value of 0.0% (p < 0.001). No recurrences were observed in the anisometropic amblyopia group, whereas recurrence occurred in two cases of the strabismic amblyopia group after finishing the vision rehabilitation process. In conclusion, the combined approach of the treatment evaluated is efficacious for providing an improvement in visual acuity and binocular function in both anisometropic and strabismic amblyopia, which was maintained over time.

The aim of the current study was to evaluate the results of a novel dichoptic training program using an online platform in a group of subjects with refractive amblyopia, performing a comparative analysis of unilateral and bilateral amblyopic cases. For this purpose, a retrospective study analysis of data of 161 children (4–13 years) who underwent dichoptic treatment with the Bynocs® platform (Kanohi Eye Pvt. Ltd., India) was performed. In all cases, the therapy protocol consisted of sessions of training of 30 min daily 5 times a week for 6 weeks. Best corrected visual acuity (BCVA) in the non-dominant eye improved significantly with the treatment, with a mean change of 0.39 logMAR in the whole sample (p < 0.001). Regarding binocularity, the binocular function (BF) score also experienced a significant improvement (p < 0.001), with a mean change of 1.55 with therapy in the whole sample. The BCVA of the dominant eye only improved significantly (p < 0.001) in the isometropic amblyopic subgroup. In conclusion, the use of the dichoptic therapy with the digital platform evaluated allows an effective restoration of visual acuity and binocular function in children with anisometropic and isometropic amblyopia.

Amblyopia results from an abnormal binocular interaction, in the context of strabismus or uncorrected refractive errors, or from visual deprivation. Screening is important during pre-school years in order to start treatment while cerebral plasticity is optimal. Screening practices vary a lot between developed countries, with consequences on public health policies. Screening is based on the measure of visual acuity in young children. The technique of sweep visual evoked potentials allows an objective measure of visual acuity, without requiring participants to name optotypes, which is useful in pre-verbal children. Along with decreased visual acuity, amblyopia is associated with an absence of improvement with age of the characteristics of saccades. With respect to motor skills, altered binocular vision affects catching skills and balance. A better understanding of these deficits will allow for better treatment of amblyopia, which is the first cause of monocular vision loss in children., (MED - Sciences médicales) -- UCL, 2022

Purpose: Approaches are developed to determine relative retinal magnifications in anisometropic patients undergoing cataract surgery; these can be used to balance between full spectacle corrections with equal intraocular lens (IOL) powers and a pure IOL power correction. Methods: The analysis started from the original and pseudophakic Navarro eye models, where in the latter case an IOL replaced the natural lens. A third model was a simplified Navarro-IOL model with a single surface cornea and a thin lens. These models were manipulated by altering vitreous length, corneal power and lens position. Retinal image sizes were determined for both full IOL corrections and full spectacle corrections by raytracing and approximate equations. Relative magnification (RM) was determined as the ratio of retinal image size of an eye to that of the appropriate standard eye. Results: For raytracing and full IOL correction, vitreous length led to RM change of 5%/mm, while for corneal power and IOL position this was −0.4%/D and 1.4%/mm, respectively. For raytracing and spectacle correction, effects were 0%/D (vitreous depth), −1.6%/D (corneal power) and +1.0%/mm (IOL position). For full IOL correction, the approximate RM calculations were highly accurate. For spectacle correction, the approximate RM calculations were exact for vitreous length changes, reasonably accurate for corneal power changes but very inaccurate for changes in anterior chamber depth. Conclusion: Relative magnification approximations may be useful to assess the risk of aniseikonia in anisometropic patients targeted for postoperative emmetropia. Some of these patients would be corrected best by a combination of spectacles and IOLs.

Purpose: We aimed to compare the depth perception under a microscope between binocular and monocular conditions using a newly developed microscopic stereotest (M-stereotest) and examine the effect of anisometropia on depth perception under a microscope. Subjects and Methods: Thirty young and healthy subjects were examined. A manipulator attached with a stainless wire was placed under the objective lens of a stereomicroscope. The wire was moved up manually, and the subjects were instructed to stop the knob movement once the wire reached the same height as the fixed two wires. The deviation from the height of the fixed wires was measured under a best optically corrected binocular, a best optically corrected monocular, or an anisometropic binocular [± 3 diopters (D) in the dominant or nondominant eye] condition. Results: The deviation was significantly smaller in the binocular condition than in the monocular dominant eye condition (0.38 ± 0.26 mm vs 1.89 ± 1.15 mm, p < 0.001) and was also significantly smaller in the best optically corrected binocular than in the anisometropic binocular condition [1.07 ± 1.00 mm (− 3.0 D), p = 0.003; 0.85 ± 0.67 mm (+3.0 D), p < 0.001]. Conclusion: Depth perception under the microscope is more accurate under the binocular than in the monocular condition, indicating the potential role of stereopsis. Anisometropia deteriorates depth perception, suggesting that refractive error should be corrected during microscopic work, such as during ophthalmic surgery.

L'ambliopia és una condició produït per un desenvolupament visual anòmal que provoca una pèrdua de l'agudesa visual i d'altres habilitats visuals binoculars. Apareix principalment en les primeres etapes de la vida i ocasiona problemes en la qualitat de vida del pacient si no es detecta a temps. L'objectiu d'aquest treball és proporcionar una actualització dels últims avenços en el tractament de l'ambliopia mitjançant la recerca bibliogràfica de documents i articles, la majoria extretes de les bases de dades Medline i PubMed. El tractament tradicional per l'ambliopia és l'oclusió de l'ull dominant mitjançant un pegat per entrenar l'ull ambliop. En els estudis més recents s'han suggerit tractaments d'aprenentatge perceptiu mitjançant videojocs i sistemes de realitat virtual per a obtenir millors resultats i millorar les habilitats visuals com la estereopsis i la sensibilitat al contrast. Però no poden considerar-se substituts dels tractaments convencionals perquè encara estan en fase d'investigació., La ambliopía es una condición producida por un desarrollo visual anómalo que provoca una pérdida de la agudeza visual y de otras habilidades visuales binoculares. Aparece principalmente en las primeras etapas de la vida y ocasiona problemas en la calidad de vida del paciente si no se detecta a tiempo. El objetivo de este trabajo es proporcionar una actualización de los últimos avances en el tratamiento de la ambliopía mediante la búsqueda bibliográfica de documentos y artículos, la mayoría extraídas de las bases de datos Medline y PubMed. El tratamiento tradicional para la ambliopía es la oclusión del ojo dominante mediante un parche para entrenar el ojo amblíope. En los estudios más recientes se han sugerido tratamientos de aprendizaje perceptivo mediante videojuegos y sistemas de realidad virtual para obtener mejores resultados y mejorar las habilidades visuales como la estereopsis y la sensibilidad al contraste. Pero no pueden considerarse sustitutos de los tratamientos convencionales porque todavía están en fase de investigación., Amblyopia is a condition produced by an abnormal visual development that causes a loss of visual acuity and other binocular visual skills. It appears mainly in the early stages of life and causes problems in the patient's quality of life if not detected early. The aim of this thesis is to provide an update on the latest advances in the treatment of amblyopia by means of a literature search of papers and articles, mostly extracted from Medline and PubMed databases. The traditional treatment for amblyopia is occlusion of the dominant eye by patching to train the amblyopic eye. More recent studies have suggested perceptual learning treatments using video games and virtual reality systems to obtain better results and improve visual skills such as stereopsis and contrast sensitivity. But they cannot be considered substitutes for conventional treatments because they are still in the research phase.

Objective: No method exists to measure aniseikonia tolerance in stereoacuity. The brain can compensate for 2%–3% aniseikonia (i.e. 2–3 dioptres of anisometropia) without impairing stereoacuity; however, a substantial proportion of anisometropic patients experience problems caused by disruptions of sensory fusion due to surgically induced aniseikonia. We hypothesized that individual differences in tolerance to aniseikonia exist and sought to develop a method to measure aniseikonia tolerance. Methods: A total of 21 eye-healthy phakic individuals older than 50 years of age and 11 patients awaiting clear lens extraction were included. Patients were tested with best corrected near and distance visual acuity, cover/uncover test, eye dominance test, stereoacuity threshold (TNO test), slit lamp examination and ocular coherence tomography. The stereoacuity threshold was determined with aniseikonia induced by different size lenses ranging from 1% to 9% magnification of both eyes in increments of 1%. The aniseikonia tolerance range (ATR) was defined as the percentage aniseikonia in which the stereoacuity threshold was maintained. Results: We examined 32 patients with a median age of 65 (95% CI: 62–66 years), CDVA better than 6/7.5 (0.1 logMAR), and median near visual acuity better than 6/6 (0.0 logMAR). The median stereoacuity threshold was 60 arcsec (maximum 30, minimum 120). We observed large inter-individual differences in ATR: 6/31 (19%) participants had an ATR of ≤1%, 1/31 (3%) had an ATR of 1-5%, 7/31 (22%) had an ATR of 5-10%, and 17/31 (54%) had an ATR of >10%. Conclusion: We present a reliable method for measuring the amount of aniseikonia that a person can tolerate without impairing stereopsis. We report large inter-individual differences in tolerance of aniseikonia.

L’ambliopia és un dèficit de la visió que succeeix en els primers anys de desenvolupament del sistema visual. Es manifesta principalment per una pèrdua de la funció binocular i una disminució de l’agudesa visual (AV) de l’ull ambliop. És la causa més freqüent de la pèrdua visual a la infància 1-3% de la població general (1-7). El tractament actual és la correcció òptica total (8) i l’oclusió monocular de l’ull no ambliop per forçar l’ull ambliop. Durant molts anys s’ha associat amb una pèrdua d’AV permanent sinó es compensava el defecte refractiu abans de la finalització del període crític de desenvolupament visual(9). .L’oclusió de l’ull no ambliop es la teràpia mes utilitzada en el tractament de l’ambliopia en nens menors de 7 anys , es practica des del segle XVIII(10-11),. Els últims estudis en aquest camp i insistint en el cas dels adults amb ambliopia , s’ha demostrat que es pot recuperar part de la AV i de la estèreo-agudesa gràcies a l’entrenament perceptiu monocular on s’argumenta una disminució de la supressió a través de l’entrenament dicòptic(12-17). En fer aquest treball m’he adonat de la gran importància que té per part de l’optometrista la realització d’un examen visual complet en el moment de sospitar de la presencia d’una possible ambliopia a l’edat primerenca per a poder tractar-la a temps i prevenir totes les disfuncions que pot causar a nivell visual., La ambliopía es un déficit en la visión que sucede en los primeros años de desarrollo del sistema visual. Se manifiesta principalmente por una pérdida de la función binocular y disminución de la agudeza visual(AV) en el ojo ambliope. Es la causa más frecuente de la pérdida visual en la infancia 1-3% de la población general(1-7).El tratamiento actual es la corrección óptica completa(8)y oclusión monocular del ojo no ambliope para forzar el ojo ambliope. Durante muchos años se ha asociado con una pérdida de AV permanente sino se compensaba el defecto refractivo antes de la finalización del periodo crítico de desarrollo visual(9). La oclusión del ojo no ambliope es la terapia más usada en el tratamiento de la ambliopía en niños menores de 7 años, se practica desde el siglo XVIII (10-11). Los últimos estudios en este campo e insistiendo en el caso de los adultos con ambliopía de larga duración han demostrado que se puede recuperar parte de la AV y de la estereoagudeza gracias al entrenamiento perceptivo monocular donde se argumenta una disminución de la supresión a través del entrenamiento dicóptico (12-17). Al realizar este trabajo me he dado cuenta de la gran importancia que tiene por parte del optometrista la realización de un examen visual completo en el momento de sospechar de presencia de una posible ambliopía en la edad temprana para poder tratarla a tiempo y prevenir todas las disfunciones que puede causar a nivel visual., L'amblyopie est la cause la plus fréquente de la perte visuelle à l'enfance 1-3 % de la population générale (1-7). Le traitement actuel est la correction optique totale (8) et l'occlusion monoculaire de l'œil non amblyope pour forcer l'œil amblyope. Pendant beaucoup d'années s'est associée à une perte d'AV permanente si le défaut de réfraction se compense pas avant la finalisation de la période critique de développement visuel(9). L'occlusion de l'œil non amblyope est la thérapie la plus utilisée dans le traitement de l'amblyopie dans des enfants plus petits de sept ans, s'utilise depuis le XVIIIe siècle(10-11). Les dernières études dans ce champ et en insistant à propos des adultes avec amblyopie de longue durée, on a démontré qu'il peut se regagner partie de l'AV et de la stéréo-acuité grâce à l'entraînement perceptif monoculaire où argumente une diminution de la suppression à travers l'entraînement dicôptic (12-17). En faisant ce travail je me suis rendu compte de grande importance qu'il a pour par l'opticien la réalisation d'un examen visuel complet lors de suspecter de l'existence d'une possible amblyopie dans l'âge printanier pour pouvoir la traiter à temps et prévenir tous les dysfonctionnements qui peuvent causer au niveau visuel.

L’ambliopia es caracteritza per una disminució de l’agudesa visual unilateral o bilateral per la privació del patró de visió o per una interacció binocular anormal i sense existir patologies oculars evidents que en siguin la causa. També es veuen afectades la visió estereoscòpica i la sensibilitat al contrast. Aquest dèficit visual afecta el 3% de la població i és la causa més comuna de pèrdua de visió binocular en nens i adults joves (National Eye Institute 2006). Segons l’etiologia i el grau de l’ambliopia s’optarà pel tractament refractiu, l’oclusió convencional, la penalització farmacològica, la teràpia visual o inclús una combinació d’aquestes. Durant l’últim quart de segle, l’oclusió convencional ha estat la primera opció de tractament de l’ambliopia, però es coneix, que cal una adherència al tractament i un seguiment regular per assegurar l’èxit de la teràpia. D’altra banda, és interessant i preocupant la interrupció en la binocularitat amb aquest tractament. La penalització farmacològica amb atropina ha estat l’alternativa a l’oclusió convencional durant més d’un segle, mostrant un índex d’adherència i una qualitat de vida majors. L'objectiu d’aquest treball és comparar, mitjançant una recerca bibliogràfica, dues de les opcions de tractament de l’ambliopia: l’oclusió convencional i la penalització farmacològica. Com a resultat de l’estudi, l’atropina sembla ser tan eficaç com l’oclusió convencional per millorar l’agudesa visual de l’ull ambliop i, pel que fa a la binocularitat, no hi ha evidències d’una diferència en l’alineació ocular i l’agudesa estereoscòpica entre els dos tipus de tractament

Report of a presentation of bilateral choroidal osteoma without neovascularization in a child following a school screening. Diagnosis was based on funduscopy, optical coherence tomography and B-scan ultrasonography. The child was followed regularly with cycloplegic refraction, funduscopy, macular SD-OCT and EDI-SD-OCT. Fluorescein angiography and OCT-angiography will be performed if necessary. Purpose: To report a peculiar presentation of bilateral choroidal osteoma in a very young child. Methods: Case report. Results: During a school screening, a 4-year-old girl was detected with anisometropia as the first sign of a bilateral choroidal osteoma. The diagnosis was based on funduscopy, optical coherence tomography and B-scan ultrasonography. Conclusion: Choroidal osteomas are rare benign tumors that can lead to severe visual loss due to progression or complications. They are found mostly in young adults, but in our case, the refractive screening allowed an early diagnosis despite the lack of visual symptoms., SCOPUS: ar.j, info:eu-repo/semantics/published

Purpose: To determine whether monocularly- and binocularly-induced spherical and meridional blur and aniseikonia had similar effects on stereopsis thresholds. Methods: Twelve participants with normal binocular vision viewed McGill modified random dot stereograms to determine stereoacuities in a four-alternative forced-choice procedure. Astigmatism was induced by placing trial lenses in front of the eyes. Twenty-three conditions were used, consisting of zero (no lens), +1 D and +2 D spheres and cylinders at axes 180, 45 and 90 in front of the right eye, and the following binocular combinations of both lens powers: R × 180/L × 180, R × 45/L × 45, R × 90/L × 90, R sphere/L sphere, R × 180/L × 90, R × 45/L × 135, R × 90/L × 180. Aniseikonia was induced by placing magnifying lenses in front of the eyes. Twenty-three conditions were used, consisting of zero, 6% and 12% overall magnification and both magnifications at axes 180, 45 and 90 in front of the right eye only, and the following binocular combinations using 3% and 6% lenses: R × 90/L × 90, R × 45/L × 45, R × 180/L × 180, R overall/L overall, R × 90/L × 180, R × 45/L × 135, and R × 180/L × 90. Results: Stereopsis losses for binocular blur effects with parallel axes (non-anisometropic) were the same as for monocular blur effects of the same axes, and these were strongly dependent on axis (spherical blur and ×90 had the greatest effects). Binocular blur effects with orthogonal axes had greater effects than with parallel axes, with the axis combination of the former having no effect (e.g. R × 90/L × 180 was similar to R × 45/L × 135). For induced aniseikonia, splitting the magnifications between the eyes improved stereopsis slightly, and the effects were not dependent on axis. Conclusion: Binocular blur affects stereopsis similarly to monocular meridional blur if axes in the two eyes are parallel, whereas the effect is greater if the axes are orthogonal. In meridional aniseikonia, splitting magnification between the

Purpose: Stereopsis depends on horizontally disparate retinal images but otherwise concordance between eyes. Here we investigate the effect of spherical and meridional simulated anisometropia and aniseikonia on stereopsis thresholds. The aims were to determine effects of meridian, magnitude and the relative effects of the two conditions. Methods: Ten participants with normal binocular vision viewed McGill modified random dot stereograms through synchronised shutter glasses. Stereoacuities were determined using a four-alternative forced-choice procedure. To induce anisometropia, trial lenses of varying power and axes were placed in front of right eyes. Seventeen combinations were used: zero (no lens) and both positive and negative, 1 and 2 D powers, at 45, 90 and 180 axes; spherical lenses were also tested. To induce aniseikonia 17 magnification power and axis combinations were used. This included zero (no lens), and 3%, 6%, 9% and 12% at axes 45, 90 and 180; overall magnifications were also tested. Results: For induced anisometropia, stereopsis loss increased as cylindrical axis rotated from 180° to 90°, at which the loss was similar to that for spherical blur. For example, for 2 D meridional anisometropia threshold increased from 1.53 log sec arc (i.e. 34 sec arc) for x 180 to 1.89 log sec arc (78 sec arc) for x 90. Anisometropia induced with either positive or negative lenses had similar detrimental effects on stereopsis. Unlike anisometropia, the stereopsis loss with induced meridional aniseikonia was not affected by axis and was about 64% of that for overall aniseikonia of the same amount. Approximately, each 1 D of induced anisometropia had the same effect on threshold as did each 6% of induced aniseikonia. Conclusion: The axes of meridional anisometropia but not aniseikonia affected stereopsis. This suggests differences in the way that monocular blur (anisometropia) and interocular shape differ

Objetivo general: Determinar la relación entre anisometropía y ambliopía, y su asociación a la visión de profundidad. Métodos: El presente trabajo de Investigación se realizó en las Instalaciones del Policlínico Club de Leones, Arequipa. Se desarrolló en el periodo comprendido entre Septiembre del año 2018 y Enero del año 2019. Se realizó un estudio de investigación aplicada, de tipo descriptivo, observacional, prospectivo, transversal, de relación. La muestra estuvo constituida por pacientes que acudieron a consulta externa en el periodo de tiempo antes mencionado quienes presentaron un error refractivo entre ambos ojos mayor a 2 dioptrías de diferencia (Anisometropía), y que se encontraran en un rango de edades entre los 4 y 40 años de edad; siendo en total una población de 45 pacientes. A quienes se les procedió a determinar la AV von y sin correctores (lentes), el descarte de presencia o no de ambliopía; y posteriormente se aplicó el TNO Steresotest para medir si había pérdida en la visión de profundidad (estereopsia). Las variables han sido investigadas y se ha recopilado la información mediante fichas de recolección de datos, la cual fue validada por médico especialista en Oftalmología. Las variables para su procesamiento han requerido del Chi cuadrado con un nivel de significancia del 5%. Resultados: El 96.6% de los pacientes que acudieron a consulta externa por el servicio de oftalmología del Policlínico Club de Leones presentaron anisometropía cilíndrica, mientras que sólo el 4.4% de los pacientes tiene anisometropía hipermetrópica. Según la prueba de chi cuadrado, se demostró que el grado de anisometropía y el grado de ambliopía presentan relación estadística significativa (P<0.05); siendo así, que el 13.3% de los pacientes que acudieron a consulta externa por el servicio de oftalmología del Policlínico Club de Leones con ambliopía leve tienen un grado de anisometropía entre 2.0 - 2.5 y 2.51 - 3.0. De acuerdo a los resultados de la investigación se acepta

ImportanceOne of the most important causes of vision abnormalities in children is amblyopia (also known as "lazy eye"). Amblyopia is an alteration in the visual neural pathway in a child's developing brain that can lead to permanent vision loss in the affected eye. Among children younger than 6 years, 1% to 6% have amblyopia or its risk factors (strabismus, anisometropia, or both). Early identification of vision abnormalities could prevent the development of amblyopia.Subpopulation considerationsStudies show that screening rates among children vary by race/ethnicity and family income. Data based on parent reports from 2009-2010 indicated identical screening rates among black non-Hispanic children and white non-Hispanic children (80.7%); however, Hispanic children were less likely than non-Hispanic children to report vision screening (69.8%). Children whose families earned 200% or more above the federal poverty level were more likely to report vision screening than families with lower incomes.ObjectiveTo update the 2011 US Preventive Services Task Force (USPSTF) recommendation on screening for amblyopia and its risk factors in children.Evidence reviewThe USPSTF reviewed the evidence on the accuracy of vision screening tests and the benefits and harms of vision screening and treatment. Surgical interventions were considered to be out of scope for this review.FindingsTreatment of amblyopia is associated with moderate improvements in visual acuity in children aged 3 to 5 years, which are likely to result in permanent improvements in vision throughout life. The USPSTF concluded that the benefits are moderate because untreated amblyopia results in permanent, uncorrectable vision loss, and the benefits of screening and treatment potentially can be experienced over a child's lifetime. The USPSTF found adequate evidence to bound the potential harms of treatment (ie, higher false-positive rates in low-prevalence populations) as small. Therefore, the USPSTF concluded with mode

We measured saccadic latencies in a large sample (total n = 459) of individuals with amblyopia or risk factors for amblyopia, e.g., strabismus or anisometropia, and normal control subjects. We presented an easily visible target randomly to the left or right, 3.5° from fixation. The interocular difference in saccadic latency is highly correlated with the interocular difference in LogMAR (Snellen) acuity-as the acuity difference increases, so does the latency difference. Strabismic and strabismic-anisometropic amblyopes have, on average, a larger difference between their eyes in LogMAR acuity than anisometropic amblyopes and thus their interocular latency difference is, on average, significantly larger than anisometropic amblyopes. Despite its relation to LogMAR acuity, the longer latency in strabismic amblyopes cannot be attributed either to poor resolution or to reduced contrast sensitivity, because their interocular differences in grating acuity and in contrast sensitivity are roughly the same as for anisometropic amblyopes. The correlation between LogMAR acuity and saccadic latency arises because of the confluence of two separable effects in the strabismic amblyopic eye-poor letter recognition impairs LogMAR acuity while an intrinsic sluggishness delays reaction time. We speculate that the frequent microsaccades and the accompanying attentional shifts, made while strabismic amblyopes struggle to maintain fixation with their amblyopic eyes, result in all types of reactions being irreducibly delayed.

We measured saccadic latencies in a large sample (total n = 459) of individuals with amblyopia or risk factors for amblyopia, e.g., strabismus or anisometropia, and normal control subjects. We presented an easily visible target randomly to the left or right, 3.5° from fixation. The interocular difference in saccadic latency is highly correlated with the interocular difference in LogMAR (Snellen) acuity-as the acuity difference increases, so does the latency difference. Strabismic and strabismic-anisometropic amblyopes have, on average, a larger difference between their eyes in LogMAR acuity than anisometropic amblyopes and thus their interocular latency difference is, on average, significantly larger than anisometropic amblyopes. Despite its relation to LogMAR acuity, the longer latency in strabismic amblyopes cannot be attributed either to poor resolution or to reduced contrast sensitivity, because their interocular differences in grating acuity and in contrast sensitivity are roughly the same as for anisometropic amblyopes. The correlation between LogMAR acuity and saccadic latency arises because of the confluence of two separable effects in the strabismic amblyopic eye-poor letter recognition impairs LogMAR acuity while an intrinsic sluggishness delays reaction time. We speculate that the frequent microsaccades and the accompanying attentional shifts, made while strabismic amblyopes struggle to maintain fixation with their amblyopic eyes, result in all types of reactions being irreducibly delayed.

Amblyopia is a neuro-developmental disorder of the visual cortex that arises from abnormal visual experience early in life. Amblyopia is clinically important because it is a major cause of vision loss in infants and young children. Amblyopia is also of basic interest because it reflects the neural impairment that occurs when normal visual development is disrupted. Amblyopia provides an ideal model for understanding when and how brain plasticity may be harnessed for recovery of function. Over the past two decades there has been a rekindling of interest in developing more effective methods for treating amblyopia, and for extending the treatment beyond the critical period, as exemplified by new clinical trials and new basic research studies. The focus of this review is on stereopsis and its potential for recovery. Impaired stereoscopic depth perception is the most common deficit associated with amblyopia under ordinary (binocular) viewing conditions (Webber & Wood, 2005). Our review of the extant literature suggests that this impairment may have a substantial impact on visuomotor tasks, difficulties in playing sports in children and locomoting safely in older adults. Furthermore, impaired stereopsis may also limit career options for amblyopes. Finally, stereopsis is more impacted in strabismic than in anisometropic amblyopia. Our review of the various approaches to treating amblyopia (patching, perceptual learning, videogames) suggests that there are several promising new approaches to recovering stereopsis in both anisometropic and strabismic amblyopes. However, recovery of stereoacuity may require more active treatment in strabismic than in anisometropic amblyopia. Individuals with strabismic amblyopia have a very low probability of improvement with monocular training; however they fare better with dichoptic training than with monocular training, and even better with direct stereo training.

Aims: The present study was planned to evaluate the prevalence of anisometropia in patients with refractive error, to compare the prevalence of different types of anisometropia and to study the prevalence of amblyopia in anisometropic patients. Material and Method: It was a cross sectional study in which 400 randomly selected patients were evaluated for anisometropia and also for anisometropic amblyopia. All patients underwent thorough ophthalmic examination including visual acuity testing, slit lamp examination and fundus examination. Later on the data was analysed statistically with different formulas like Chi square test, Fisher exact test etc. Results: The prevalence of anisometropia was found to be 16.5% in total 400 patients with refractive errors, out of which 57.5% were females and 42.5% were male patients. Prevalence was found maximum in 20-30 years age group (36.4%). Highest prevalence among various types of anisometropia was found of compound myopic anisometropia (37.9%). Conclusion: No gender difference was seen in prevalence of anisometropia. Prevalence of anisometropia significantly varied with different age groups. The prevalence of amblyopia in patients of anisometropia was found to be statistically significant (p value=.0001).

El sistema visual está formado por órganos, vias y centros nerviosos, que permiten captar y procesar lo que nos rodea. El ojo es el órgano que se encarga de la captación de imágenes y las lleva a la retina. Sin embargo, cuando la córnea, o la longitud axial del ojo, no es la correcta, la imagen se ve borrosa, y, mediante lentes oftálmicas, podemos neutralizar esa borrosidad o ametropía. Una anisometropía es la diferencia de graduación entre ambos ojos, que componen el sistema visual binocular. Al neutralizar con lentes oftálmicas esta graduación, se generan una imágenes en la retina de diferente tamaño, dando lugar a una aniseiconia; el cerebro las puede procesar si la diferencia de medida entre las imágenes, o factor de aumento de las lentes, no supera el 5%. Este trabajo consiste en analizar las posibilidades de minimizar las aniseiconías, y para ello se van a evaluar los parámetros de los que depende el factor de aumento de una lente. También se valorará el espesor de la lente oftálmica y su peso en la gafa para comprobar que es funcional. Una vez analizados todos los datos, se llega a la conclusión de que no se dispone de suficientes combinaciones de lentes oftálmicas, que puedan ser utilizadas como neutralizadoras de ametropías, sin que causen una aniseiconía al paciente, que comprometa su visión binocular

Purpose To investigate the impact of a relatively low level of simulated hyperopic anisometropia on children’s ability to perform academic-related tasks before and after sustained near work. Methods Sixteen children (11.1 ± 0.8 years) with normal vision were recruited. Performance on standardized academic-related outcome measures was assessed with and without 0.75 D of hyperopic anisometropia simulation (in randomized order), immediately following the introduction of the simulation and again after 20 minutes of sustained near work. Academic-related measures included a standardized reading test (Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from Wechsler Intelligence Scale for Children) and a reading-related eye movement test (Developmental Eye Movement test). The unilateral defocus was systematically assigned to either the dominant or non-dominant sighting eye to evaluate the influence of ocular dominance on any performance decrements. Results Simulated hyperopic anisometropia and sustained near work both independently impaired academic-related performance (p < 0.05). Conclusions Simulated hyperopic anisometropia impaired children’s performance on a range of academic–related outcome measures, especially following a period of sustained near work. This suggests that low levels of hyperopic anisometropia, which may not be typically corrected in clinical practice, could have a detrimental impact on academic-related performance in children.

Purpose: This study investigated the impact of simulated hyperopic anisometropia and sustained near work on performance of academic-related measures in children. Methods: Participants included 16 children (mean age: 11.1 ± 0.8 years) with minimal refractive error. Academic-related outcome measures included a reading test (Neale Analysis of Reading Ability), visual information processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children) and a reading-related eye movement test (Developmental Eye Movement test). Performance was assessed with and without 0.75 D of imposed monocular hyperopic defocus (administered in a randomised order), before and after 20 minutes of sustained near work. Unilateral hyperopic defocus was systematically assigned to either the dominant or non-dominant sighting eye to evaluate the impact of ocular dominance on any performance decrements. Results: Simulated hyperopic anisometropia and sustained near work both independently reduced performance on all of the outcome measures (p<0.001). A significant interaction was also observed between simulated anisometropia and near work (p<0.05), with the greatest decrement in performance observed during simulated anisometropia in combination with sustained near work. Laterality of the refractive error simulation (ocular dominance) did not significantly influence the outcome measures (p>0.05). A reduction of up to 12% in performance was observed across the range of academic-related measures following sustained near work undertaken during the anisometropic simulation. Conclusion: Simulated hyperopic anisometropia significantly impaired academic–related performance, particularly in combination with sustained near work. The impact of uncorrected habitual anisometropia on academic-related performance in children requires further investigation.

Antimetropia, a sub-classification of anisometropia, is a rare refractive condition in which one eye is myopic and the fellow eye is hyperopic. This case report describes the ocular characteristics and atypical refractive progression in an adult male with a moderate degree of non-amblyopic antimetropia over a 20-year period. The potential mechanisms underlying unilateral axial elongation, anisometropia and myopia progression in adulthood are discussed.

PurposeTo investigate the association of hyperopia greater than +3.25 diopters (D) with amblyopia, strabismus, anisometropia, astigmatism, and reduced stereoacuity in preschoolers.MethodsThree- to five-year-old Head Start preschoolers (N = 4040) underwent vision examination including monocular visual acuity (VA), cover testing, and cycloplegic refraction during the Vision in Preschoolers Study. Visual acuity was tested with habitual correction and was retested with full cycloplegic correction when VA was reduced below age norms in the presence of significant refractive error. Stereoacuity testing (Stereo Smile II) was performed on 2898 children during study years 2 and 3. Hyperopia was classified into three levels of severity (based on the most positive meridian on cycloplegic refraction): group 1: greater than or equal to +5.00 D, group 2: greater than +3.25 D to less than +5.00 D with interocular difference in spherical equivalent greater than or equal to 0.50 D, and group 3: greater than +3.25 D to less than +5.00 D with interocular difference in spherical equivalent less than 0.50 D. "Without" hyperopia was defined as refractive error of +3.25 D or less in the most positive meridian in both eyes. Standard definitions were applied for amblyopia, strabismus, anisometropia, and astigmatism.ResultsRelative to children without hyperopia, children with hyperopia greater than +3.25 D (n = 472, groups 1, 2, and 3) had a higher proportion of amblyopia (34.5 vs. 2.8%, p < 0.0001) and strabismus (17.0 vs. 2.2%, p < 0.0001). More severe levels of hyperopia were associated with higher proportions of amblyopia (51.5% in group 1 vs. 13.2% in group 3) and strabismus (32.9% in group 1 vs. 8.4% in group 3; trend p < 0.0001 for both). The presence of hyperopia greater than +3.25 D was also associated with a higher proportion of anisometropia (26.9 vs. 5.1%, p < 0.0001) and astigmatism (29.4 vs. 10.3%, p < 0.0001). Median stereoacuity of nonstrabismic, nonamblyopic c

PurposeAnisometropia shows an exponential increase in prevalence with increasing age based on cross-sectional studies. The purpose of this study was to evaluate longitudinal changes in anisometropia in all refractive components in older observers and to assess the influence of early cataract development.MethodsRefractive error was assessed at two time points separated by approximately 12 years in 118 older observers (aged 67.1 and 79.3 years at the two test times). Anisometropia defined as greater than or equal to 1.00 D was calculated for all refractive components. The subjects had intact ocular lenses in both eyes throughout the study. Lens evaluations were performed at the second test using the Lens Opacities Classification System III.ResultsAll refractive components approximately doubled in prevalence of anisometropia. Spherical equivalent anisometropia changed from 16.1 to 32.2%. Similar changes were found for spherical error (17 to 38.1%), primary astigmatism (7.6 to 17.8%), and oblique astigmatism (14.4 to 29.7%). Many who did not have anisometropia at the first visit subsequently developed anisometropia (e.g., 26.3% for spherical error and 22.9% for oblique cylinder). The onset of anisometropia occurred at all ages within the studied age range, with no particular preference for any one age. A small number lost anisometropia over time. Individual comparisons of refractive error changes in the two eyes in combination with nuclear lens changes showed that early changes in nuclear sclerosis in the two eyes could account for a large proportion of anisometropia (~40%), but unequal hyperopic shift in the spherical component in the two eyes was the primary cause of the anisometropia.ConclusionsAnisometropia is at least 10 times more common in the elderly than in children, and anisometropia develops in all refractive components in the oldest observers. Clinicians need to be aware of this common condition that could lead to binocular vision problems and potentially ca

The case of a male patient aged 32 who come to refractive surgery consultation at the Hospital "Amistad Argelia Cuba” is presented in May 2012 for surgical correction of visual defects. History and complete eye examination was done in the left eye and Artisan phakic lens implant was performed and in a month right eye was corrected by in situ keratomileusis (LASIK). The postoperative follow-up was performed at the third and sixth months without complications. This combination can be a surgical alternative for correction high myopia patients and anisometropia. No induced astigmatism appeared nor postoperative ectasia. The variation in the endothelial cell count is negligible in relation to the surgical technique. A significant improvement in visual acuity without postoperative correction which results in higher quality and visual satisfaction was obtained., Se presenta el caso de un paciente masculino de 32 años de edad que acude a la consulta de cirugía refractiva del Hospital Oftalmológico “Amistad Argelia Cuba” en mayo de 2012 para corrección quirúrgica de su defecto visual. Se realiza anamnesis y examen ocular completo. En el ojo izquierdo se realizó implante de lente fáquico Artisan y al mes se corrigió el ojo derecho mediante queratomileusis in situ asistida por láser (LASIK). El seguimiento posquirúrgico se efectuó al tercer y sexto mes sin complicaciones. Esta combinación quirúrgica puede ser una alternativa de corrección para pacientes miopías elevadas y anisometropías. No apareció astigmatismo inducido ni ectasia posquirúrgica. La variación en el conteo celular endotelial resulta ser insignificante en relación a la técnica quirúrgica. Se obtuvo una significativa mejoría de la agudeza visual sin corrección post operatoria lo cual se traduce en una mayor calidad y satisfacción visual.

Purpose: To examine the symmetry of corneal changes following near work in the fellow eyes of non-amblyopic myopic anisometropes. Methods: Thirty-four non-amblyopic, myopic anisometropes (minimum 1 D spherical equivalent anisometropia) had corneal topography measured before and after a controlled near work task. Subjects were positioned in a headrest to minimise head movements and read continuous text on a computer monitor for 10 minutes at an angle of 25 degrees downward gaze and an accommodation demand of 2.5 D. Measures of the morphology of the palpebral aperture during primary and downward gaze were also obtained. Results: The more and less myopic eyes exhibited a high degree of interocular symmetry for measures of palpebral aperture morphology during both primary and downward gaze. Following the near work task, fellow eyes also displayed a symmetrical change in superior corneal topography (hyperopic defocus) which correlated with the position of the upper eyelid during downward gaze. Greater changes in the spherical corneal power vector (M) following reading were associated with narrower palpebral aperture during downward gaze (p = 0.07 for more myopic and p = 0.03 for less myopic eyes). A significantly greater change in J0 (an increase in against the rule astigmatism) was observed in the more myopic eyes (-0.04 ± 0.04 D) compared to the less myopic eyes (-0.02 ± 0.06 D) over a 6 mm corneal diameter (p = 0.01). Conclusions: Changes in corneal topography following near work are highly symmetrical between the fellow eyes of myopic anisometropes due to the interocular symmetry of the palpebral aperture. However, the more myopic eye exhibits changes in corneal astigmatism of greater magnitude compared to the less myopic eye.

Purpose: To determine the prevalence of myopia in school children in Greater Beijing. Methods: The Beijing Childhood Eye Study was a school-based cross-sectional study. One school of each level (primary, junior high, senior high) was randomly selected from nine randomly selected districts of Greater Beijing. The children underwent non-cycloplegic refractometry and their parents an interview. Results: Of 16 771 eligible students, 15 066 (89.8%) children with a mean age of 13.2 ± 3.4 years (range: 7-18 years) participated. Prevalence of myopia defined as refractive error of ≤-0.50 diopters (D), ≤-1.00 D, ≤-6.00 D and ≤-8.00 D in the right eye was 64.9 ± 0.4%, 53.0 ± 0.4%, 4.3 ± 0.2% and 1.0 ± 0.1% respectively. In multivariate analysis, prevalence of myopia was significantly (p < 0.001) associated with higher age, female gender, urban region and school type. Prevalence of myopia of ≤-1.00 D and of ≤-8.0 D increased from 9.7% and 0% in 7 year olds, respectively, to 74.2% and 1.8% in 17- or 18 year olds respectively. The latter figure was already similar (p = 0.39) to the prevalence of high myopia in the elderly Beijing Eye Study population (1.6%). In a subset of 1082 children undergoing cycloplegia, difference in refractive error between prior to and after cycloplegia was 0.31 ± 0.47 diopters. Conclusions: On the basis of previous investigations from China, our study indicated an ongoing myopic shift in the young generation. Since the prevalence of high myopia in children aged 17 or 18 years was already similar to the one in the elderly Beijing population, the data prognosticate an increase in vision threatening high myopia in the future adult population.

Purpose: To examine between eye differences in corneal higher order aberrations and topographical characteristics in a range of refractive error groups. Methods: One hundred and seventy subjects were recruited including; 50 emmetropic isometropes, 48 myopic isometropes (spherical equivalent anisometropia ≤ 0.75 D), 50 myopic anisometropes (spherical equivalent anisometropia ≥ 1.00 D) and 22 keratoconics. The corneal topography of each eye was captured using the E300 videokeratoscope (Medmont, Victoria, Australia) and analyzed using custom written software. All left eye data were rotated about the vertical midline to account for enantiomorphism. Corneal height data were used to calculate the corneal wavefront error using a ray tracing procedure and fit with Zernike polynomials (up to and including the eighth radial order). The wavefront was centred on the line of sight by using the pupil offset value from the pupil detection function in the videokeratoscope. Refractive power maps were analysed to assess corneal sphero-cylindrical power vectors. Differences between the more myopic (or more advanced eye for keratoconics) and the less myopic (advanced) eye were examined. Results: Over a 6 mm diameter, the cornea of the more myopic eye was significantly steeper (refractive power vector M) compared to the fellow eye in both anisometropes (0.10 ± 0.27 D steeper, p = 0.01) and keratoconics (2.54 ± 2.32 D steeper, p < 0.001) while no significant interocular difference was observed for isometropic emmetropes (-0.03 ± 0.32 D) or isometropic myopes (0.02 ± 0.30 D) (both p > 0.05). In keratoconic eyes, the between eye difference in corneal refractive power was greatest inferiorly (associated with cone location). Similarly, in myopic anisometropes, the more myopic eye displayed a central region of significant inferior corneal steepening (0.15 ± 0.42 D steeper) relative to the fellow eye (p = 0.01). Significant interocular differences in higher order aberrations were only observed

PURPOSE: To examine the symmetry of corneal changes following near work in the fellow eyes of non-amblyopic myopic anisometropes. METHODS: Thirty-four non-amblyopic myopic anisometropes (minimum 1 D spherical equivalent anisometropia) were recruited. Corneal topography was measured with the Medmont E300 Videokeratoscope before and after a controlled near task. Subjects were positioned to minimise head movements and read continuous text on a computer monitor for 10 minutes at an angle of 25 degrees downward gaze and an accommodation demand of 2.5 D. Measures of palpebral aperture morphology during primary and downward gaze were also obtained using digital photography and analysed with customised software. RESULTS: Significant changes in corneal topography were observed after ten minutes of reading. Localised superior regions of corneal topographical change (a hyperopic shift in corneal power) were typically exhibited in both eyes following the near task. The mean change in the corneal sphero-cylinder was +0.02/-0.11 x 113 and +0.02/-0.06 x 68 for the more and less myopic eyes respectively for a 6 mm corneal diameter. A significantly greater change in corneal astigmatism power vector J0 (a larger increase in against the rule astigmatism) was observed in the more myopic eyes (p < 0.01 for a 6 mm diameter). The more and less myopic eyes exhibited a high degree of interocular symmetry for measures of palpebral aperture morphology during both primary and downward gaze. Changes in corneal power vectors following reading were associated with eyelid position during downward gaze. CONCLUSIONS: Changes in corneal topography observed following a controlled reading task were highly symmetrical between the fellow eyes of myopic anisometropes due to the interocular symmetry of the palpebral aperture. However, the more myopic eye did exhibit a small but significantly greater magnitude of change in corneal astigmatism compared to the less myopic eye following reading. These findings

Purpose: To investigate the interocular symmetry of optical, biometric and biomechanical characteristics between the fellow eyes of myopic anisometropes. Methods: Thirty-four young, healthy myopic anisometropic adults (≥ 1 D spherical equivalent difference between eyes) without amblyopia or strabismus were recruited. A range of biometric and optical parameters were measured in both eyes of each subject including; axial length, ocular aberrations, intraocular pressure (IOP), corneal topography and biomechanics. Ocular sighting dominance was also measured. Results: Mean absolute spherical equivalent anisometropia was 1.70 ± 0.74 D and there was a strong correlation between the degree of anisometropia and the interocular difference in axial length (r = 0.81, p < 0.001). The more and less myopic eyes displayed a high degree of interocular symmetry for the majority of biometric, biomechanical and optical parameters measured. When the level of anisometropia exceeded 1.75 D, the more myopic eye was more likely to be the dominant sighting eye than for lower levels of anisometropia (p=0.002). Subjects with greater levels of anisometropia (> 1.75 D) also showed high levels of correlation between the dominant and non-dominant eyes in their biometric, biomechanical and optical characteristics. Conclusions: Although significantly different in axial length, anisometropic eyes display a high degree of interocular symmetry for a range of anterior eye biometrics and optical parameters. For higher levels of anisometropia, the more myopic eye tends to be the dominant sighting eye.

PURPOSE To determine the prevalence of amblyopia, anisometropia, and strabismus in schoolchildren of Shiraz, Iran. MATERIALS AND METHODS A random cluster sampling was used in a cross-sectional study on schoolchildren in Shiraz. Cycloplegic refraction was performed in elementary and middle school children and high school students had non-cylcoplegic refraction. Uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded for each participant. Anisometropia was defined as spherical equivalent (SE) refraction difference 1.00D or more between two eyes. Amblyopia was distinguished as a reduction of BCVA to 20/30 or less in one eye or 2-line interocular optotype acuity differences in the absence of pathological causes. Cover test was performed for investigating of strabismus. RESULTS Mean age of 2638 schoolchildren was 12.5 years (response rate = 86.06%). Prevalence of anisometropia was 2.31% (95% confidence interval [CI], 1.45 to 3.16). 2.29% of schoolchildren (95% CI, 1.46 to 3.14) were amblyopic. The prevalence of amblyopia in boys and girls was 2.32% and 2.26%, respectively (p = 0.945). Anisometropic amblyopia was found in 58.1% of the amblyopic subjects. The strabismus prevalence was 2.02% (95% CI, 1.18 to 2.85). The prevalence of exotropia and esotropia was 1.30% and 0.59%, respectively. CONCLUSIONS Results of this study showed that the prevalence of anisometropia, amblyopia, and strabismus are in the mid range. The etiology of amblyopia was often refractive, mostly astigmatic, and non-strabismic. Exotropia prevalence increased with age and was the most common strabismus type.

PURPOSE: To investigate the interocular symmetry of ocular optical, biometric and biomechanical characteristics between the more and less ametropic eyes of myopic anisometropes. METHODS: Thirty-four young, healthy myopic anisometropic adults (≥ 1 D spherical equivalent difference between eyes) without amblyopia or strabismus were recruited. A range of biometric and optical parameters were measured in the more and less ametropic eye of each subject including; axial length, ocular aberrations, intraocular pressure and corneal topography, thickness and biomechanics. Morphology of the anterior eye in primary and downward gaze was examined using custom software analysis of high resolution digital images. Ocular sighting dominance was assessed using the hole-in-the-card test. RESULTS: Mean absolute spherical equivalent anisometropia was 1.74 ± 0.74 D. There was a strong correlation between the degree of anisometropia and the interocular difference in axial length (r = 0.81, p < 0.001). The more and less ametropic fellow eyes displayed a high degree of interocular symmetry for the majority of biometric, biomechanical and optical parameters measured. When the level of anisometropia exceeded 1.75 D (n = 10), the more myopic eye was the dominant sighting eye in nine of these ten subjects. Subjects with greater levels of anisometropia (> 1.75 D) also showed high levels of correlation between the dominant and non-dominant eyes in their biometric, biomechanical and optical characteristics. CONCLUSIONS: Although significantly different in axial length, anisometropic eyes display a high degree of interocular symmetry for a range of anterior eye biometrics and optical parameters. For higher levels of anisometropia, the more myopic eye tends to be the dominant sighting eye.

To evaluate whether luminance contrast discrimination losses in amblyopia on putative magnocellular (MC) and parvocellular (PC) pathway tasks reflect deficits at retinogeniculate or cortical sites. Fifteen amblyopes including six anisometropes, seven strabismics, two mixed and 12 age-matched controls were investigated. Contrast discrimination was measured using established psychophysical procedures that differentiate MC and PC processing. Data were described with a model of the contrast response of primate retinal ganglion cells. All amblyopes and controls displayed the same contrast signatures on the MC and PC tasks, with three strabismics having reduced sensitivity. Amblyopic PC contrast gain was similar to electrophysiological estimates from visually normal, non-human primates. Sensitivity losses evident in a subset of the amblyopes reflect cortical summation deficits, with no change in retinogeniculate contrast responses. The data do not support the proposal that amblyopic contrast sensitivity losses on MC and PC tasks reflect retinogeniculate deficits, but rather are due to anomalous post-retinogeniculate cortical processing of retinal signals.

The basis of treatment for amblyopia (poor vision due to abnormal visual experience early in life) for 250 years has been patching of the unaffected eye for extended times to ensure a period of use of the affected eye. Over the last decade randomised controlled treatment trials have provided some evidence on how to tailor amblyopia therapy more precisely to achieve the best visual outcome with the least negative impact on the patient and the family. This review highlights the expansion of knowledge regarding treatment for amblyopia and aims to provide optometrists with a summary of research evidence to enable them to better treat amblyopia. Treatment for amblyopia is effective, as it reduces overall prevalence and severity of visual loss in this population. Correction of refractive error alone significantly improves visual acuity, sometimes to the point where further amblyopia treatment is not required. Atropine penalisation and patch occlusion are effective in treating amblyopia. Lesser amounts of occlusion or penalisation have been found to be just as effective as greater amounts. Recent evidence has highlighted that occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life. These complications should be considere when prescribing treatment because they can negatively affect compliance. Studies investigating the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion are ongoing.

While corneal refractive surgery offers the potential to reduce dependence on optical appliances and widen the potential candidate pool, residual optical effects from such elective surgery can impact quality of vision and visual performance not identified using the traditional 20/20 standard derived from a high contrast Snellen-type letter chart. The major area of postoperative concern following photorefractive keratectomy (PRK) found in this study was the potential for residual refractive errors, including undercorrection, overcorrection, induced astigmatism, and anisometropia. Low to moderate residual refractive error after refractive surgery may be operationally significant in aviators, especially if not optimally corrected. The prevalence in this study for PRK-treated eyes to have low to moderate residual refractive errors, defined as equal to or more than -0.50 D of myopia (spherical equivalent) on cycloplegic refraction, was relatively high. Yet, very few of these subjects wore corrective lenses to meet current standards. The fundamental question is whether most individuals, particularly aviators, will wear relatively minor optical corrections in spectacles after refractive surgery, especially if they meet the current 20/20 requirement uncorrected and are therefore not required to wear corrective lenses. Failure to do so, however, may mean that certain visual performance parameters would be compromised and could potentially result in operational limitations of significance in addition to reduced contrast sensitivity and degraded performance under impoverished environmental conditions., Prepared in collaboration with the 859th MSGS/MCST (Lackland AFB, TX), Northrop Grumman, and Conceptual Mindworks, Inc. (San Antonio, TX). The original document contains color images.

Amblyopia, defined as poor vision due to abnormal visual experience early in life, affects approximately three per cent of the population and carries a projected lifetime risk of visual loss of at least 1.2 per cent. The presence of amblyopia or its risk factors, mainly strabismus or refractive error, have been primary conditions targeted in childhood vision screenings. Continued support for such screenings requires evidence-based understanding of the prevalence and natural history of amblyopia and its predisposing conditions, and proof that treatment is effective in the long term with minimal negative impact on the patient and family. This review summarises recent research relevant to the clinical understanding of amblyopia, including prevalence data, risk factors, the functional impact of amblyopia and optimum treatment regimes and their justification from a vision and life skills perspective. Collectively, these studies indicate that treatment for amblyopia is effective in reducing the overall prevalence and severity of visual loss from amblyopia. Correction of refractive error alone has been shown to significantly reduce amblyopia and less frequent occlusion can be just as effective as more extensive occlusion. Occlusion or penalisation in amblyopia treatment can create negative changes in behaviour in children and impact on family life, and these factors should be considered in prescribing treatment, particularly because of their influence on compliance. Ongoing treatment trials are being undertaken to determine both the maximum age at which treatment of amblyopia can still be effective and the importance of near activities during occlusion. This review highlights the expansion of current knowledge regarding amblyopia and its treatment to help clinicians provide the best level of care for their amblyopic patients that current knowledge allows.

The refractive estate is described in pediatrically normal infants under 12 months of age. The infants that were examined came from the Hospital Tunjuelito‐ Clinical El Carmen population, who participated in the “Growth and development program” Refraction was measured by dynamic retinoscopy. The most common refractive states found were: Astigmatism (77% RE, 73.5% LE)with the rule (100% RE, 97.4% LE) hipermetropic in both meridians or hipermetropic and myopic. The positive and negative spherical component in the right eye fluctuated between 0.25 – 1.50 diopters; in the left eye the positive was 0.25 – 0.75 and the negative 1.00 – 1.50 diopters. The cylindrical magnitudes were below 2.50 diopters RE, 3.00 diopters LE (73.8% RE, 66.6% LE). The anisometropic values were low; only 1 infant was 2.50 diopters anisometropic., Describe el estado refractivo en niños menores de un año de edad. Los niños examinados proceden de la población pediátrica del hospital de Tunjuelito‐ Clínica El Carmen, que asisten al “Programa de Crecimiento y Desarrollo”. La refracción fue determinada mediante la técnica de retinoscopia dinámica. Los estados refractivos encontrados más comúnmente fueron: Astigmatismo (77.5% OD, 73.5 OI: con la regla 100% OD 97.4% OI) del tipo hipermétrope compuesto y mixto. El componente esférico positivo y negativo encontrado en el ojo derecho oscilo entre 0.25 y 1.50 dioptrías, en el ojo izquierdo y el componente esférico positivo fluctuó entre 0.25 y 0.75 dioptrías (70%) el negativo entre 1 y 1.50 dioptrías (52%). La magnitud del valor cilíndrico fue menor a 2.50 dioptrías (%) y en OI a 3.00 dioptrías (73.8% OD, 66.6% OI). El valor de anisometropia fue bajo, solo un niño presento 2.50 de anisometropia.

To establish the results of refractive screening of preschool children with the hand-held autorefractor Retinomax under non-cycloplegic conditions, and to compare these results with those of photoscreening., Comparative Study, Journal Article, Research Support, Non-U.S. Gov't, SCOPUS: ar.j, info:eu-repo/semantics/published

Anisometropia may be responsible for aniseikonia. and anisophoria. In children, aniseikonia may create amblyopia. It is of utmost importance to distinguish axial from refractive anisometropia. When the anisometropia is axial in origin, spectacle lenses constitute the treatment of choice (Knapp's law). On the contrary, when the anisometropia is refractive in origin, contact lenses represent the first choice of treatment.

Fifty non-strabismic children with primary anisometropia were reviewed retrospectively. At entry, patients ranged in age from 1 to 10 years with an average of 4.5 years. The follow-up ranged from 0.5 to 9 years with an average of 3.5 years. Criteria for inclusion were a difference in refractive error between the two eyes of at least 1.00 D of spherical value and/or 0.75 D of cylindrical value. In all cases, anisometropia was totally corrected by prescribing glasses. Anisometropic amblyopia was considered to be present when isoacuity at far was not reached despite the glasses, part-time occlusion therapy of the good eye was prescribed. Amblyopia was present in 86% of the patients and was found with all types of anisometropia. It was more severe in anisohyperopia and/or anisoastigmatism. After adequate treatment, amblyopia was clinically cured or less severe in 78% of the patients.

Fifty non-strabismic children with primary anisometropia were reviewed retrospectively. At entry, patients ranged in age from 1 to 10 years with an average of 4.5 years. The follow-up ranged from 0.5 to 9 years with an average of 3.5 years. Criteria for inclusion were a difference in refractive error between the two eyes of at least 1.00 D of spherical value and/or 0.75 D of cylindrical value. In all cases, anisometropia was totally corrected by prescribing glasses. Anisometropic amblyopia was considered to be present when isoacuity at far was not reached despite the glasses, part-time occlusion therapy of the good eye was prescribed. Amblyopia was present in 86% of the patients and was found with all types of anisometropia. It was more severe in anisohyperopia and/or anisoastigmatism. After adequate treatment, amblyopia was clinically cured or less severe in 78% of the patients.

An Important feauture of monovision correction is the ability of the binocular system to suppress blur from the defocused eye (interocular blur suppression). We conducted a study with three subjects and found that interocular blur suppression improved with higher levels of monocular defocus (addition powers in monovision) but was not affected by the eye defocused (sighting dominant or non‐domninant) or by pupil size. The selection and management of monovision patients may be assisted by an understading of the understanding of the underlying suppression preocesses.

Recently it has been demonstrated that saccades become different in size in the two eyes if a subject is adapted to anisometropic spectacles, which provide visual images of different magnitude to the two eyes. These nonconjugate adaptations adequately meet the requirements of those spectacles and, once acquired, they persist (with some reduction) even during monocular viewing. We now demonstrate that such nonconjugate adaptations of saccades can be meridian-specific, if there is a pressure for such meridian-specificity. This pressure was provided by means of a cylindrical spectacle-lens. Adaptations along a vertical, horizontal or oblique meridian did not transfer to the orthogonal meridian. These results demonstrate a capability of saccadic adaptation to deal with calibration problems restricted not only to one eye, but even to one specific plane of muscular action. Our results also suggest that the meridian-specific adaptations of oblique saccades take place at a stage before the decomposition of motor commands into separate horizontal and vertical components. The meridian-specific nonconjugacies were also expressed in smooth-pursuit eye movements. Post-saccadic drift adapted only along the horizontal meridian.